Wireless or cordless telephony systems are well known. A radio frequency wireless telephony system uses a well-known technology whose characteristics have both advantages and disadvantages. In such an RF system the transmitter components are relatively small, light, and low in power consumption compared to the receiver components which are heavy power consumers.
In using an RF system, there is no need to have a line-of-sight relation between the transmitter and the receiver; but one disadvantage of this is that the RF signal can be monitored at a distance.
Another aspect of RF is the regulatory environment in certain countries such as Canada and the U.S.A. A two-way RF system has regulatory restrictions in Canada and the U.S.A., although a one-way voice communication system (e.g. a wireless microphone) is currently permitted.
In contrast to an RF system, a two-way IR (infra-red) system is not currently subject to government regulation (in Canada and the U.S.A.). An IR system is suitable for multi-channel use. In an open-office environment, a line-of-sight relation is needed between the transmitter and the receiver, and a warning signal may be needed to correct operator misuse (i.e. alerting the operator to an interruption of the beam or to moving out of range).
In contrast to the RF system, the receiver components of an IR system are relatively small, light, and low in power consumption, whereas the IR transmitter requires much more power than does the RF transmitter.